JP6119664B2 - Circuit assembly and electrical junction box - Google Patents

Description

  The technique disclosed by this specification is related with a circuit structure and an electrical junction box.

  2. Description of the Related Art Conventionally, as a device that performs energization or disconnection of an in-vehicle electrical component, a device in which a circuit structure including a circuit board on which various electronic components are mounted is accommodated in a case is known.

  In such an apparatus, an electronic component mounted on a circuit board is small and has an excellent function.

JP 2013-99071 A

  However, since these electronic components generate a relatively large amount of heat, if the heat generated from the electronic components is trapped in the case, the inside of the case becomes hot, and the performance of the electronic components housed in the case may deteriorate. It was.

  Therefore, as various structures for radiating the heat generated from the circuit board and the electronic component, for example, as shown in FIG. 7, a heat radiating member is provided on the surface of the circuit board 112 opposite to the surface on which the electronic component 115 is disposed. A circuit structure 111 having a configuration in which 130 is provided is conceivable.

  On the other hand, as shown in FIGS. 6 and 7, an opening 113 is provided in a region of the circuit board 112 corresponding to the electronic component 115, and the surface of the circuit board 112 opposite to the surface on which the electronic component 115 is disposed. A configuration in which a plurality of bus bars 120 are provided and the terminals 117 of the electronic component 115 are connected to the bus bars 120 exposed through the openings 113 is conceivable. By configuring a power circuit with a plurality of bus bars 120, a large current can flow through the power circuit.

  However, when the electronic component 115 is connected to the plurality of bus bars 120 through the openings 113 provided in the circuit board 112, as shown in FIG. 7, the heat dissipating member laminated on the surface of the bus bar 120 on the opposite side of the circuit board 112. In some cases, the adhesive 135 for bonding enters the gap S between the adjacent bus bars 120 and contacts the lower surface of the main body 116 of the electronic component 115. In such a state, when the adhesive 135 expands due to heat generated from the circuit board 112 or the electronic component 115, or conversely, when the shrinkage occurs due to cooling, the electronic component 115 is pushed up by the adhesive 135 or pulled in. There is a risk that a connection failure such as a crack may occur in the connection portion between the terminal 117 and the bus bar 120.

  The technology disclosed in the present specification has been completed based on the above-described circumstances, and an object thereof is to provide a circuit structure and an electrical junction box with high connection reliability.

  The technology disclosed in the present specification includes a substrate having a connection opening, a plurality of bus bars stacked on one surface side of the substrate via an adhesive sheet, a main body portion, and a plurality of lead terminals. By connecting the lead terminals to the plurality of bus bars exposed through the connection openings, electronic components disposed on the other surface side of the substrate, and on the surface of the plurality of bus bars opposite to the substrate A heat sink laminated with an adhesive, wherein the adhesive sheet exposes the plurality of bus bars and connects the plurality of lead terminals to the plurality of bus bars. It has a sheet opening and covers gaps between the plurality of bus bars located in the connection opening.

  According to the technology disclosed in the present specification, the gap between adjacent bus bars is covered with the adhesive sheet in the connection opening, so that the adhesive that has entered the gap is the lower surface of the main body of the electronic component. Direct contact with the is prevented. Further, since the adhesive sheet arranged in this way has an action of suppressing the adhesive in the gap, it is possible to reduce the influence that the electronic component receives from the adhesive as compared with the case where the adhesive sheet is not arranged. . Therefore, a circuit structure and an electrical junction box with high connection reliability can be obtained.

  The technology disclosed in the present specification is an electrical junction box in which the above-described circuit structure is housed in a case.

  According to the technology disclosed in this specification, connection reliability can be improved in a circuit configuration body or an electrical junction box.

The exploded perspective view of a part of circuit composition object of one embodiment Top view inside the electrical junction box Partially enlarged plan view of the connection opening before arranging the coil Partially enlarged plan view of the coil connected to the bus bar Partial sectional view taken along line AA of FIG. Partially enlarged plan view of a state where a coil is connected to a bus bar according to virtual technology Partial sectional view taken along line BB in FIG.

  One embodiment will be described with reference to FIGS.

  The electrical junction box 10 according to the present embodiment includes a circuit board 11 including a circuit board 12 and a heat sink 30, and a synthetic resin case 40 that houses the circuit board 11. In the following description, the upper side in FIG. 1 is described as the front side or the upper side, and the lower side is described as the back side or the lower side.

  As shown in FIG. 1, the circuit structure 11 includes a circuit board 12, a coil 15 (an example of an electronic component) disposed on the front surface (upper surface in FIG. 1) of the circuit board 12, and the back surface of the circuit board 12 (FIG. 1 is provided with a plurality of bus bars 20 disposed on the lower surface of the bus bar 20 and a heat sink 30 (see FIG. 5) disposed on the back surface of the bus bar 20.

  The circuit board 12 has a substantially L shape, and a conductive circuit (not shown) is formed on the surface thereof by a printed wiring technique.

  The coil 15 is a surface-mount type coil, and has a rectangular parallelepiped main body 16 as shown in FIGS. 1 and 5, and a pair of edges around the edges of two opposing sides of the bottom surface of the main body 16. The lead terminal 17 is provided.

  The plurality of bus bars 20 are formed by pressing a metal plate into a predetermined shape. The bus bar 20 has a generally rectangular shape, and is arranged in a predetermined pattern with a gap S between adjacent bus bars 20. A connecting piece 21 protruding outward is formed integrally with the bus bar 20 at the side edge of some bus bars 20. Bolt mounting holes 21A for inserting bolts are formed through these connection pieces 21. Bolts (not shown) are inserted into these bolt mounting holes 21A and screwed with power supply terminals mounted on the vehicle. As a result, the connection piece 21 is electrically connected to an external power source.

  The plurality of bus bars 20 are bonded to the back surface of the circuit board 12 via an insulating adhesive sheet 25. The outer shape of the adhesive sheet 25 is substantially the same as the outer shape of the circuit board 12.

  As shown in FIG. 1, a connection opening 13 for mounting the coil 15 on the bus bar 20 is formed at a position on the circuit board 12 where the coil 15 is disposed. As shown in FIG. 4, the portion of the connection opening 13 where the main body portion 16 of the coil 15 is disposed opens in a rectangular shape slightly larger than the bottom surface of the main body portion 16. In addition, an opening having a short width (hereinafter referred to as an extension portion 13A) is provided on the side of the pair of edges where the lead terminal 17 of the coil 15 is located. A part of the pair of bus bars 20 is disposed in the connection opening 13.

  On the other hand, the adhesive sheet 25 is provided with a pair of sheet openings 26 for mounting the lead terminals 17 of the coil 15 on the bus bar 20. As shown in FIG. 3, the seat opening 26 is a substantially square opening, and a part of the seat opening 26 is provided at a position overlapping the pair of expansion portions 13 </ b> A. More specifically, the seat opening 26 is provided such that a part of the opening edge is located slightly outside the opening edge of the expansion portion 13A (so as to have a slightly larger opening size), A part of the bus bar 20 is exposed in the connection opening 13 of the circuit board 12.

  Further, the seat opening 26 is provided in the connection opening 13 so that the opening edge thereof does not cover the gap S between the adjacent bus bars 20. In other words, the adhesive sheet 25 is configured to cover the gap S between the adjacent bus bars 20 from the upper surface side in the connection opening 13.

  The coil 15 is disposed on the surface side of the circuit board 12 in a region where the connection opening 13 is provided. In this embodiment, the lead terminal 17 of the coil 15 is connected to the surface of the bus bar 20 exposed through the connection opening 13 and the sheet opening 26 by a known method such as soldering.

  A heat radiating plate 30 is disposed on the lower surface (back surface) of the bus bar 20 (see FIG. 5). The heat radiating plate 30 is a plate-shaped member made of a metal material having excellent thermal conductivity such as aluminum or aluminum alloy, and has a function of radiating heat generated in the circuit board 12 and the coil 15. The heat sink 30 is bonded to the back side of the bus bar 20 with, for example, a thermosetting adhesive 35. The adhesive 35 is an adhesive having insulating properties and thermal conductivity.

  Then, an example of the manufacturing process of the electrical junction box 10 which concerns on this embodiment is demonstrated. First, as shown in FIG. 1, an adhesive sheet 25 cut into a predetermined shape is overlaid on a lower surface of a circuit board 12 having a conductive path formed on the surface thereof by a printed wiring technique, and a plurality of bus bars 20 are connected to predetermined surfaces. Pressurize in a state where they are arranged in a pattern. Thereby, the circuit board 12 and the plurality of bus bars 20 are bonded and fixed to each other via the adhesive sheet 25. In this state, part of the upper surfaces of the plurality of bus bars 20 (regions where the lead terminals 17 of the coils 15 are mounted) are exposed through the connection openings 13 of the circuit board 12 and the sheet openings 26 of the adhesive sheet 25. It is in a state.

  Subsequently, solder is applied to a predetermined position of the circuit board 12 by screen printing. Thereafter, the coil 15 is placed at a predetermined position, and reflow soldering is executed.

  Next, the adhesive 35 is applied to the upper surface of the heat sink 30, and the circuit board 12 on which the coil 15 and the plurality of bus bars 20 are arranged is overlapped from above. At this time, since the gap S between the adjacent bus bars 20 located in the connection opening 13 of the circuit board 12 is covered with the adhesive sheet 25, the adhesive 35 that has entered the gap S is the main body of the coil 15. There is no direct contact with the lower surface of the part 16 (see FIG. 5). Thereafter, the adhesive 35 is cured by heating.

  Finally, the circuit board 12 (circuit structure) on which the heat dissipation plate 30 is overlaid is accommodated in the case 40 to obtain the electrical connection box 10.

  Then, the effect | action and effect of the electrical junction box 10 which concern on this embodiment are demonstrated. According to the present embodiment, even when the adhesive 35 enters the gap S between the adjacent bus bars 20 in the connection opening 13, the adhesive 35 is suppressed in the gap S by the adhesive sheet 25. Therefore, even when the adhesive 35 expands due to heat or contracts conversely, the influence of the coil 15 from the adhesive 35 can be reduced as compared with the case where the adhesive sheet 25 is not disposed. That is, it is possible to obtain a circuit structure and an electrical junction box with high connection reliability.

<Other embodiments>
The technology disclosed in the present specification is not limited to the embodiments described with reference to the above description and drawings, and includes, for example, the following various aspects.

  (1) In the above embodiment, the configuration in which the pair of lead terminals 17 is connected to the bus bar 20 is shown. For example, one of the lead terminals 17 may be connected to the conductive path of the circuit board 12, and in this case, One sheet opening 26 of the adhesive sheet 25 may be provided.

  (2) The position, shape, and number of the seat openings 26 are not limited to the above embodiment, and can be changed as appropriate. The point is that the lead terminal 17 can be connected to the bus bar 20 and the adhesive sheet 25 covers the gap S between the adjacent bus bars 20.

  (3) Although the example which mounts the coil 15 was shown in the said embodiment, it is applicable not only when the coil 15 but other electronic components, such as a capacitor | condenser and shunt resistance, are mounted.

DESCRIPTION OF SYMBOLS 10 ... Electric junction box 11 ... Circuit structure 12 ... Circuit board 13 ... Connection opening 15 ... Coil 16 ... Main-body part 17 ... Lead terminal 20 ... Bus bar 25 ... Adhesive sheet 26 ... Sheet opening part 30 ... Heat sink 35 ... Adhesion Agent 40 ... Case S ... Gap

Claims (2)

A substrate having a connection opening;
A plurality of bus bars laminated on one side of the substrate via an adhesive sheet;
An electronic component having a main body and a plurality of lead terminals, wherein the lead terminals are connected to the plurality of bus bars exposed through the connection opening;
A heat dissipating plate laminated with an adhesive on the surface opposite to the substrate among the plurality of bus bars, and a circuit structure comprising:
The adhesive sheet includes a sheet opening for exposing the plurality of bus bars to connect the plurality of lead terminals to the plurality of bus bars, and the plurality of bus bars positioned in the connection opening. A circuit structure that covers the gaps between them. An electrical junction box comprising the circuit structure according to claim 1 housed in a case.

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